1. Field of the Invention
The present invention relates to an ultrasound diagnosis apparatus for providing a map of an interest index, and more particularly, to an ultrasound diagnosis apparatus for providing at least one of a mechanical index (MI) map, an acoustic pressure map, and a thermal index (TI) map according to various standards such as a depth value, a scan line, time, and the like, and an ultrasound diagnosis method.
2. Description of the Related Art
Ultrasound diagnosis apparatuses transmit an ultrasound signal toward a predetermined part of the body from a body surface of an object and obtain a tomogram of soft-tissues or an image of blood flow by using information regarding the ultrasound signal reflected by tissues of the body.
Ultrasound diagnosis apparatuses have various advantages, for example, a compact size, low cost, and real-time display. Also, ultrasound diagnosis apparatuses have excellent stability because there is no fear of radiation exposure, and thus, the ultrasound diagnosis apparatuses are widely used together with various other diagnosis apparatuses, such as computerized tomography scanners, magnetic resonance imaging (MRI) apparatuses, nuclear medicine diagnosis apparatuses, or the like.
In general, the output (a transmission voltage, pressure, and energy) of an ultrasound diagnosis apparatus is limited by an international standard, for example, a mechanical index (MI), and is determined. In this regard, the MI is an index that represents quantified mechanical effects of ultrasound on a human body.
The international standard also includes a thermal index (TI). As well known, international acceptable standards of the MI and the TI are less than 1.9 and less than 6.0, respectively.
Ultrasound diagnosis apparatuses increase a transmission voltage of an ultrasound signal that is output from a pulsar to more accurately diagnose an object. As the transmission voltage of the ultrasound signal is increased, image sensitivity improves, while an MI or acoustic pressure may be increased.
A high MI (or acoustic pressure) means that an ultrasound diagnosis apparatus has a greater effect on a human body. Also, if the MI (or acoustic pressure) is increased over a predetermined level, the use of the corresponding ultrasound diagnosis apparatus is restricted by an international standard.
In consideration of such a problem, a transmission voltage of an ultrasound diagnosis apparatus needs to be accurately controlled to sufficiently increase the transmission voltage and to maintain an MI, acoustic pressure, and a TI, which are interest indexes, having values less than a threshold value.
However, recently, only an interest index of a reference value that is simply represented numerically is provided without careful consideration to a value of a depth of interest, which is a distance in a direction in which ultrasound travels from a pulse output part of an ultrasound diagnosis apparatus to a part to be diagnosed. In other words, there is provision of visualized data about an interest index that is necessary for a user of an ultrasound diagnosis apparatus to control a transmission voltage in order to increase image sensitivity.